Jul 2026· International journal of phytoremediation· pp.
1-16
· 0 citations· 74 references
Medicine
TL;DR
Overall, exogenous NH₄HCO₃modulates rhizosphere soil properties and reshapes fungal communities, which may improve plant growth and enhance Cd phytoaccumulation in Populus yunnanensis Dode.
Abstract
Cadmium (Cd) poses a threat to plant growth. Nitrogen (N) has been demonstrated to alleviate Cd phytotoxicity, but the underlying mechanism in woody plants remains unclear. In this study, we aimed to determine whether exogenous NH₄HCO₃ influences rhizosphere soil properties and fungal communities, thereby enhancing plant growth and Cd phytoaccumulation in Populus yunnanensis Dode. A pot experiment was conducted in a greenhouse, with seedlings subjected to four treatments: CK (no additional N and Cd), N (24 mg N kg-1 month-1 supplied as NH₄HCO₃), Cd (20 mg Cd kg-1 month-1), and CN (24 mg N kg-1 and 20 mg Cd kg-1 month-1). Under Cd stress, exogenous NH₄HCO₃ increased the biomass (48.0-78.2%), root development, nutrient content, and Cd accumulation (149.2%). In rhizosphere soil, exogenous NH₄HCO₃ decreased the soil pH and NH4+-N content but increased the NO3--N content, available phosphorus (AP), and soil enzyme activities. Exogenous NH₄HCO₃ also reshaped the composition, structure, and co-occurrence patterns of the rhizosphere fungal community, altering the relative abundances of saprotrophic and ectomycorrhizal fungi, such as Rhizoctonia, Peziza, and Exophiala. Moreover, Rhizoctonia and Peziza were positively and negatively correlated with AP, alkaline phosphatase, root biomass, root surface area (RA), fine root surface area (FRA), and Cd uptake efficiency, respectively. Exophiala was positively correlated with root biomass, RA, and FRA. Overall, exogenous NH₄HCO₃ modulates rhizosphere soil properties and reshapes fungal communities, which may improve plant growth and enhance Cd phytoaccumulation.
Low-level bioavailable cadmium (Cd) and copper (Cu) in agricultural soils poses a severe threat to soil health and food safety; however, the mechanisms by which indigenous Cu-Cd tolerant rhizobia modulate plant-microbe-soil interactions remain poorly understood. In this field trial, the effects of two Cu-Cd tolerant strains, Sinorhizobium xinjiangense YN5 (RB) and Rhizobium pusense GF4 (RD), when inoculated individually and in combination (RC), were assessed with respect to soybean growth, heavy‑metal partitioning, rhizosphere and nodule endophytic microbiomes, and soil functional genes under bioavailable Cu-Cd stress. RB treatment significantly promoted aboveground growth parameters (plant height, node number, and pod per plant) and biomass accumulation, whereas RC treatment favored root development and maximized the reduction in soybean Cd accumulation. Rhizobia elevated Cu concentrations in leaves, while enhanced root sequestration curtailed Cd translocation to stems and pods, thereby diminishing Cd accumulation across all organs. Soil available nutrients, soil organic matter, and nitrogenase activity were significantly increased, whereas bioavailable Cd and Cu declined. Rhizobia strengthened cooperative interactions within the rhizosphere community, with positive associations accounting for 86.56% of network links under RB. Nodule symbiotic networks exhibited greater modularity and integration, and source tracking analysis revealed that RB markedly increased microbial transfer from the rhizosphere to nodules, reaching 85.2%. Rhizobia activated function associated with carbon and sulfur cycling genes. Collectively, indigenous Cu-Cd tolerant rhizobia mitigate heavy metal stress and strengthen nutrient cycling microbial functions, presenting a promising eco-compatible strategy to enhance legume productivity in agricultural soils facing low-level bioavailable heavy metal exposure.
Xinyi Li, Han-jun Liu, Tian-Bo Jia et al.· Ecotoxicology and Environmen...· 0 citations
It is shown that endophytic fungi have the potential to enhance plants’ resilience and provide a promising controlled-environment approach to enhance crop productivity in metal- and salt-contaminated soils.
Sobia Khan, Salman Khan, Afshan Afshan et al.· PLoS ONE· 0 citations
Cadmium (Cd) accumulation in plants poses a serious risk to crop growth and human health. Although rhizobacteria are known to enhance plant Cd tolerance, research on rhizobacterial consortium to alleviate Cd toxicity in crops under hydroponic conditions remains limited. Two rhizobacterial strains, Bacillus cereus TLMC1 and Pseudomonas putida TLMC5, exhibiting high Cd tolerance and strong plant growth-promoting (PGP) traits, were selected to investigate their synergistic effects on Artemisia selengensis Turcz under Cd stress. Single and co-inoculation significantly decreased shoot Cd content and increased root Cd content, with co-inoculation yielding the lowest Cd translocation factors (0.08 and 0.09 under 1 and 10 mg L-1 Cd stress, respectively). Co-inoculation maximally reduced SOD and POD activities by 27.52% and 20.34% under 1 mg L-1 Cd stress. Soluble sugars, soluble proteins, vitamin C, and total flavonoids in edible shoots were all elevated, with co-inoculation showing optimal performance. Despite the reduction of Target Hazard Quotient (THQ) after inoculation, the minimum value remained above the safety threshold. These findings demonstrated that TLMC1 and TLMC5 co-inoculation effectively reduced Cd uptake and enriched nutritional and active components in the edible parts of A. selengensis, offering a preliminary microbial strategy for Cd risk mitigation in moderately Cd-polluted regions.
Mi Shen, Wei Kang, Ruofei Liu et al.· International journal of phy...· 0 citations
Cadmium (Cd) is a highly toxic element that impairs plant growth and disrupts soil metabolism. Biochar is widely used to remediate Cd-contaminated soil; however, its immobilization performance may be altered by aging, particularly under different water regimes. In this study, a pot experiment was conducted to investigate the combined effects of biochar (0, 1.5%, and 3.0% w/w) and water management (50%, 60%, and 70% field capacity) on maize physiological responses, rhizosphere soil enzymatic activity, and bacterial communities in Cd-contaminated soil. Compared with deficit irrigation, full irrigation (70% θf) mitigated Cd-induced photosynthetic impairment more effectively. Antioxidant parameters responded differently to water and biochar: POD activity, SOD activity, and MDA content increased with increasing soil moisture, whereas CAT activity and GSH content decreased. The addition of biochar reduced POD and CAT activity, whereas the responses of SOD and GSH were V shaped. Soil moisture and biochar significantly influenced microbial community richness and diversity, and the M-B2 treatment (60% θf + 3% biochar) optimized bacterial diversity and promoted the enrichment of Sphingomonas (21.18%); these effects were linked to higher antioxidant enzyme activity. This pot-scale study provides reliable experimental evidence for the synergistic effects of water and biochar on maize seedlings under Cd stress and suggests a mechanistic framework that warrants further validation under field conditions.
Cai-Ling Yang, Kaichuan Hu, Weibiao Han et al.· Ecotoxicology and Environmen...· 0 citations
Elevated atmospheric carbon dioxide (ECO2) is a key climatic factor influencing the resilience of plant–microbial symbiotic systems against heavy metal contamination. Robinia pseudoacacia–rhizobia symbiosis shows great potential for cadmium (Cd) remediation. However, the mechanism by which ECO2 regulates Cd phytostabilization in symbiosis remains unclear. This study conducted a 90-day experiment in growth chambers to investigate the effects of ECO2 on the growth, Cd accumulation and chemical forms, as well as nutrient uptake and antioxidant system in Robinia pseudoacacia–rhizobia symbiosis. Results indicated that ECO2 significantly increased plant biomass and photosynthetic efficiency while significantly raising Cd content in roots (34.5%, p < 0.001) and decreasing it in shoots (31.4%, p < 0.001). This resulted in a significant reduction in Cd translocation factor (TF). Meanwhile, ECO2 markedly increased Cd accumulation in roots (81.2%, p < 0.001) and reduced the bioavailability of Cd in the symbiosis. Moreover, ECO2 promoted the content of nutrients and stimulated the antioxidant system. The random forest model indicated that root weight, Cd and Mn contents are the core factors for ECO2-driven Cd phytostabilization. This study demonstrates that ECO2 enhanced Cd phytostabilization by optimizing the resistance of symbiosis to Cd, offering a novel perspective for predicting plant–microbe joint restoration of heavy metal pollution under global climate change scenarios.
Xun Wang, Ruo-Shi Wang, Shao-Xiong Lin et al.· Toxics· 0 citations
Abstract Greenhouse tomato cultivation faces challenges such as nutrient imbalance and declining soil health, requiring sustainable biostimulant strategies. Objective: This study aimed to evaluate the synergistic effects of humic acid (HA) and arbuscular mycorrhizal fungi (AMF) on tomato growth, yield, and nutritional quality. Tomato plants were subjected to four treatments: control, HA alone, AMF alone, and combined HA+AMF. Growth parameters, biochemical composition, and mineral content were analyzed. Results: The combined HA+AMF treatment significantly enhanced shoot length (+50.4%), root length (+32.1%), fruit yield (+415.2%), and lycopene content (+395.3%) compared to the control. Increases in proteins, sugars, flavonoids, and key minerals (K, P, Mg) were also observed. Molecular analysis confirmed upregulation of stress-related and nutrient transporter genes. The HA+AMF synergy markedly improves tomato productivity and fruit quality, offering an eco-efficient solution for sustainable agriculture in semi-arid conditions..
N. Tolepbayeva, B. Kedelbaev, A. Uspabayeva et al.· Brazilian Journal of Biology· 0 citations
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